1. Field of the Invention
The present invention relates to a scintillator panel, a radiation image sensor, and a method of making a scintillator panel.
2. Related Background Art
Needs for radiation image sensors for detecting and capturing radiation images rapidly with high accuracy have been increasing in the fields of medicine, industry, and the like. For responding to these needs, a radiation image sensor comprising a scintillator for converting a radiation image to an optical image, an imaging device for capturing this optical image, and an optical fiber bundle for guiding to the imaging device the optical image outputted from the scintillator has been known, for example. Also known is a radiation image sensor which, in order to capture a relatively large radiation image, employs a plurality of optical fiber bundles so for guiding to a plurality of imaging devices the optical image outputted from the scintillator, and uses the plurality of imaging devices so as to capture the image.
On the other hand, Japanese Patent Application Laid-Open No. HEI 8-211155, for example, discloses a radiation image sensor in which an optical fiber bundle whose optical fiber axis forms an acute angle with the entrance end face is arranged such that the gaps between optical fibers widen from the entrance end face side to the exit end face side while their edges on the entrance end face side abut against each other. When such a radiation image sensor is used, the dead space of optical fiber bundle on the entrance end face side becomes quite smaller, whereby radiation images are prevented from partly dropping off.
However, the radiation image sensors in accordance with the above-mentioned prior art have the following problem. Namely, for carrying out imaging with high accuracy in a radiation image sensor, it is necessary to polish the entrance end face of optical fiber bundle in order to enhance its planarity. Here, in the above-mentioned radiation image sensor in which the optical fiber bundle is arranged such that edges on the entrance end face side abut against each other, edge portions are likely to chip off when the entrance end face is polished. As a consequence, a dead space occurs in the chipped-off part, whereby drops may occur in radiation images.
Therefore, it is an object of the present invention to overcome the above-mentioned problem and provide a radiation image sensor having a very small dead space and enabling highly accurate imaging, a scintillator panel used therein, and a method of making the scintillator panel.
For overcoming the above-mentioned problem, the scintillator panel of the present invention comprises an optical component in which a plurality of optical members, each having entrance and exit end faces substantially parallel to each other and being composed of a plurality of optical fibers arranged, are arranged such that the entrance end faces are disposed on substantially the same plane and side faces adjacent each other are bonded with an adhesive; and a scintillator deposited on the entrance end faces arranged; wherein at least one of the optical members adjacent each other has an optical fiber axis forming an acute angle with the entrance end face; wherein each of the optical members adjacent each other is arranged such that the optical fibers respectively constituting each of the optical members have a gap therebetween widening from the entrance end face side to the exit end face side; and wherein each side face of the optical members adjacent each other on the entrance end face side is formed with a ground surface in which the optical members are ground against each other.
Since optical members which have an optical fiber axis forming an acute angle with the entrance end face are arranged such that the gap between optical fibers widens from the entrance end face side to the exit end face side, and are bonded in a state where they are ground against each other on the entrance side, the dead space occurring at the boundary face between optical members can be made extremely small. Further, since the ground surface is formed on the side face on the entrance end face side, the entrance end face does not chip off even when polished, whereby dead spaces can be prevented from occurring due to the chipping-off. Therefore, highly accurate radiation images can be outputted.
Also, for overcoming the above-mentioned problem, the radiation image sensor of the present invention comprises the above-mentioned scintillator panel, and an imaging device for capturing an optical image outputted from the exit end face of the optical member.
The dead space occurring at the boundary face between optical members can be made extremely small by use of the above-mentioned scintillator panel, and the optical image outputted from the exit end face of optical members can be captured since the imaging device is provided. As a result, highly accurate radiation images can be captured.
Also, for overcoming the above-mentioned problem, the method of making a scintillator panel in accordance with the present invention is a method of making a scintillator panel in which a plurality of optical members, each having entrance and exit end faces substantially parallel to each other and being composed of a plurality of optical fibers arranged, are arranged such that the entrance end faces are disposed on substantially the same plane, and a scintillator is deposited on the entrance end faces arranged; the method comprising: a processing step of processing the optical members such that an axis of the optical fibers forms an acute angle with the entrance end face; an arrangement step of arranging each of the optical members adjacent each other such that the optical fibers respectively constituting each of the optical members have a gap therebetween widening from the entrance end face side to the exit end face side; a grinding step of grinding respective side faces of the optical members adjacent each other against each other so as to form a ground surface on each of the respective side faces of the optical members adjacent each other on the entrance end face side; a bonding step of bonding with an adhesive the side faces adjacent each other; and a depositing step of depositing a scintillator on the entrance end faces arranged.
Since optical members which have an optical fiber axis forming an acute angle with the entrance end face are arranged such that the gap between optical fibers widens from the entrance end face side to the exit end face side, and are bonded in a state where they are ground against each other on the entrance side, the dead space occurring at the boundary face between optical members can be made extremely small. Further, since the ground surface is formed on the side face on the entrance end face side, the entrance end face does not chip off even when polished, whereby dead spaces can be prevented from occurring due to the chipping-off. As a result, a scintillator panel which can output highly accurate radiation images can be made.